ORIGINS …

LEARNING GOALS

• I WILL BE ABLE TO EXPLAIN THE THEORY FOR THE FORMATION OF OUR SOLAR SYSTEM.

• I WILL BE ABLE TO EXPLAIN THE BIG BANG THEORY.

OUR EXPANDING UNIVERSE

• UNTIL 1920S, ASTRONOMERS THOUGHT THE MILKY WAY WAS THE ENTIRE UNIVERSE.

• THEY THOUGHT DISTANT NEBULAS WERE ONLY GAS AND DUST. (NO LUMINOUS BODIES)

• EDWIN HUBBLE IDENTIFIED INDIVIDUAL STARS INSIDE THE ANDROMEDA GALAXY AND REALIZED IT WAS A COMPLETELY DIFFERENT GALAXY FROM OURS.

• ALSO NOTICED MORE DISTANT GALAXIES THAT WERE MOVING FURTHER AWAY.

RED SHIFT

• EACH GALAXY EMITS ITS OWN DISTINCT SPECTRUM OF LIGHT.

• LIGHT SPECTRA SHIFT, DEPENDING ON WHETHER THE LIGHT SOURCE IS MOVING OR STATIONARY.

• HUBBLE NOTICED A RED SHIFT – THE LIGHT FROM THE GALAXIES SHIFTED TOWARD THE RED END OF THE SPECTRUM.

• THIS MEANT THE GALAXY WAS MOVING AWAY.

• TODAY, USED AS EVIDENCE THAT THE UNIVERSE IS EXPANDING.

DARK MATTER & ENERGY

• STARS TRAVEL AT IMMENSE SPEEDS INSIDE A GALAXY BASED ON THE MASS OF THE GALAXY ITSELF.

• STARS MOVED FASTER THAN ORIGINALLY EXPECTED LEADING TO BELIEVE THAT THERE WAS INVISIBLE MASS CAUSING THIS SPEED.

• THEY CONCLUDED THAT THERE MUST BE 10X MORE MASS IN THE GALAXY THAT WE COULD SEE WITH TELESCOPES.

• IT IS THE GRAVITY OF THIS MASS THAT IS HOLDING THE GALAXIES TOGETHER. THEY CALL THIS MATTER DARK MATTER (DOES NOT EMIT OR ABSORB LIGHT).

• IN 1998 SCIENTISTS DISCOVERED THAT NOT ONLY IS THE UNIVERSE EXPANDING, BUT THAT THE RATE OF EXPANSION IS INCREASING.

• DARK ENERGY: THE “STRANGE” FORM OF ENERGY WORKING AGAINST GRAVITY TO CAUSE UNIVERSE EXPANSION.

THE BIG BANG THEORY

• “THE UNIVERSE BEGAN IN AN INCREDIBLY HOT, DENSE, EXPANSION APPROXIMATELY 13.7 BILLION YEARS AGO”.

• FIRST DESCRIBED BY BELGIAN PRIEST AND ASTROPHYSICIST GEORGES LEMAITRE.

• OVER HUNDREDS OF MILLIONS OF YEARS THIS MATTER EXPANDED AND FORMED CLUMPS WHICH EVENTUALLY FORMED THE GALAXIES AND STARS WE SEE TODAY.

• MOST WIDELY ACCEPTED EXPLANATION OF OUR UNIVERSE.

BIG BANG THEORY EVIDENCE

• 1965: PHYSICISTS CONDUCTED EXPERIMENTS USING HIGHLY SENSITIVE ANTENNA. IT WAS THOUGHT THAT RADIATION LEFT FROM BIG BANG WAS CAUSING INTERFERENCE.

• 1989: COBE SATELLITE DETECTS TEMPERATURE VARIATIONS IN UNIVERSE >> SIMILAR TO FOSSIL RECORDS ON EARTH.

• 2001: WMAP SATELLITE PROVIDES MORE DETAILED MEASUREMENTS THAN COBE. FOUND EVIDENCE THAT THE FIRST STARS SHONE 200-300 MILLION YEARS AFTER BIG BANG.

FUTURE OF THE UNIVERSE?

• IN 2006, ASTRONOMERS CONFIRMED THAT THE EXPANSION RATE OF THE UNIVERSE BEGAN SPEEDING UP ABOUT 5 TO 6 BILLION YEARS AGO.

• OVER TIME, THE EFFECT OF THE DARK ENERGY WILL INCREASE PULLING APART GALAXIES AND LEAVING THE UNIVERSE FILLED WITH EVEN MORE COLD EMPTY SPACE.

SOLAR NEBULA THEORY

• ACCORDING TO THE SOLAR NEBULA THEORY THE SOLAR SYSTEM WAS FORMED APPROX. 5 BILLION YEARS AGO FROM A MASSIVE CLOUD OF GAS AND DUST (SOLAR NEBULA).   �

• THE COLLAPSING NEBULA STARTED A SPINNING MOTION – THIS IS WHY EARTH ORBITS THE SUN.

LEARNING GOALS REVISITED

• I WILL BE ABLE TO EXPLAIN THE THEORY FOR THE FORMATION OF OUR SOLAR SYSTEM.

• I WILL BE ABLE TO EXPLAIN THE BIG BANG THEORY.

YOUR TURN …

• PG. 397 # 1, 4, 5.